1. Field of the Invention
This invention relates generally to a composite, integral, polymeric spectacle part. More particularly, the present invention relates to an integral spectacle part which includes a first elastomeric polymer member and a second substantially rigid polymer member which have been bonded together by heat fusion to form the integral spectacle part. The present invention also relates to a method for forming a composite, integral polymeric part.
2. Description of the Prior Art
The construction of spectacle parts to be used in holding a pair of lenses adjacent to the eyes of a wearer involves many compromises with respect to the nature of the parts. In general, the spectacle frames which are used to hold the lenses need to be of rigid construction to prevent the lenses from being inadvertently removed from the frame. The parts of the spectacle which are in contact with the head of the wearer are generally required to have non-abrasive, smooth, and resilient properties. These parts of the spectacle, which include the bridge between the frames, the nasal engaging pads and the curved portion of the bow which fits over the ears of the wearer are preferably fabricated from a smooth, resilient material which will not irritate the portions of the head of the wearer in which these parts come in contact. This is particularly true for spectacles which are designed for use for athletic purposes.
It is well known to manufacture spectacles from two or more dissimilar materials which are joined together by a mechanical attachment or by use of an adhesive.
For example, U.S. Pat. No. 3,584,939 to Olson et al. describes a spectacle frame which has a central bridge member upon which is mounted a coating of resilient material. The coating of resilient material completely encircles the bridge portion of the spectacle frame and extends partially around the nasal side of each lens support.
U.S. Pat. No. 4,666,265 to Takeda describes a slim spectacle rim part which is molded from a thermoplastic resin reinforced with short fibers. The spectacle rim part of the Takeda Patent is so rigid that a frame lock joint construction is required for the spectacle rims. Frame lock joint construction refers to a type of open rim, usually metal but in the case of the Takeda Patent made of plastic reinforced with carbon fiber, which is secured around a lens by means of screws inserted into interconnecting portions of the rim.
U.S. Pat. No. 4,390,256 to Bononi discloses a nose pad for spectacles having a high elasticity.
U.S. Pat. No. 4,142,784 to Bononi describes an eyeglass frame having nose pads which can be snapped into and out of the frame.
U.S. Pat. No. 4,021,103 to Gaspari discloses an eyeglass frame having ring-like lens receiving liners. The frames are rigid and the liners into which the frames are inserted are made of a flexible plastic.
U.S. Pat. No. 4,674,851 to Jannard discloses sunglasses to which a variety of nose pad pieces can be fitted.
U.S. Pat. No. 4,222,640 to Bononi discloses safety glasses having a hard plastic inner frame or core which is completely covered by a soft, elastic polyurethane foam.
U.S. Pat. No. 3,402,005 to Liautaud et al. is directed to eyeglasses wherein the hinged ends of the temple pieces are made of a stiff, temple portion provided adjacent to a spectacle hinge, wherein the temple portion adjacent the wearer's ear is softened and otherwise treated for adjustable bending.
The variety of construction of spectacle parts, as evidenced by the citation of the foregoing patents, indicates that it would be desirable to provide a composite spectacle part which has properties designed for the purpose to which the particular part is intended to be used. In particular, it would be desirable to provide a spectacle construction wherein rigid frames are provided for holding the lens and resilient, smooth elastomeric portions are provided for those parts which are adjacent to the areas which are in contact with the wearer's head. Such parts would include the bridge portion between the frames, the nasal tabs on the frames and the ear engaging portion of the spectacle bow.
Accordingly, it is a principle object of the present invention to provide a composite, integral polymeric spectacle part which has different functional features at different portions of the part.
It is another object of the present invention to provide a method for forming a composite, integral polymeric spectacle part wherein different polymeric portions of the spectacle part are fused together to provide the integral spectacle part.
It is a further object of present invention to provide a method for forming an integral, composite polymeric part where two or more polymeric materials are bonded together by heat fusion.
These and other objects will become more apparent from the following detailed description of the invention.